were lighted by the dome. The exterior of this dome is
twelve-sided, with flat angle pilasters and level moulded plaster
cornice. It has evidently been repaired by the Turks. The inside,
however, preserves the Byzantine work. It is in twenty-four concave
apartments pierced by twelve windows, of which those facing the west
cross arm of the church are blind. As the original west window still
shows from the inside, though built up, it would appear that the
gynecaeum dome was added after the completion of the main church. At
present the open bay is ceiled by the woodwork that forms the floor of
the tribune occupied by the Sultan when he attends worship in the
mosque.[405] A door in the northern wall of the north bay communicates
with the narthex of the north church, while a door in the eastern wall
of the bay gives access to the central church. Two doors in similar
positions in the bay at the south end of the narthex led to buildings
which have disappeared. The three doors leading from the narthex into
the church are framed in red marble, the other doors in white marble.
The main dome of the church is in sixteen compartments, and is pierced
by as many windows. Its arches rest on four shafted columns, somewhat
Gothic in character, and crowned with capitals distinctly Turkish. These
columns have replaced the columns of porphyry, seven feet in
circumference, which Gyllius saw bearing the arches of the dome when he
visited the church: 'maximum (tectum) sustentatur quatuor columnis
pyrrhopoecilis, quarum perimeter habet septem pedes.'[406] The southern
wall is lighted by a triple window in the gable and a row of three
windows below the string-course. The northern wall was treated on the
same plan, but with the modifications rendered necessary by the union of
the church with the earlier central church. The triple windows in the
gable of that wall are therefore almost blocked by the roof of the
central church against which it is built; while the three windows below
the string-course are blind and are cut short by the arch opening into
the central church, as that arch rises higher than the string-course.

As explained, the gynaeceum above the inner narthex is divided by the
open central bay of that narthex into two compartments, each consisting
of two bays. The bays to the south are narrow, with transverse arches of
decidedly elliptical form. A window divided by shafts in three lights,
now built up, stood in the bay at the extreme